The overall objectives of this project are to study the characteristics of specific retinal and cortical disorders of human vision, using psychophysical and electrophysiological techniques, with the aim of increased understanding of their etiology and improved techniques of diagnosis. We applied the flicker modulation technique to populations of patients with certain diseases having retinal involvement. The two diseases chosen for study were retinitis pigmentosa and glaucoma. We developed a fast electrophysiological means of measuring visual acuity in adults and infants for use as a clinical test. We studied the range of binocular facilitation in normals and various classes of amblyopia and strabismus. Marked facilitation was found even in patients with deep amblyopia, under conditions of high contrast stimulation. We investigated the degree of localization in the VEP and hence the functional properties of local retinal-cortical processing. The responses from local retinal areas seemed to be much simpler, typically showing only one peak in the spatiotemporal frequency map. Responses were obtained from fields which should stimulate cortical areas as small as 3 x 3 mm.